Metallica's "Ride the Lightning," "And Justice for All," and "Blackened" are the first, and currently only, tracks to be affected. The three songs were released on the Rock Band store back in November 2007.

Speaking about the potential removal of songs from the Rock Band library, Harmonix said on Facebook that "our Music Team has been hard at work extending these licenses to make sure that this has as small an impact on the community as possible, but there may be a very limited number of songs that will no longer be offered for new purchases in the Rock Band store."

At present, customers who have already purchased the content will be unaffected by the removal of the songs and will be able to download them if required.

Harmonix says that future updates on Rock Band DLC relicensing will likely arrive on a quarterly basis. The developer says it is "making it a priority" to give players notice ahead of content expiring.

"We'll do our best to make sure that you have one last chance to buy these legacy catalog tracks," said Harmonix.

The final downloadable track for Harmonix's Rock Band Store, "American Pie" by Don McLean, was released on April 2. In total, the store saw over 4,000 tracks released across 275 consecutive weeks.

"We're incredibly proud of the DLC milestones we've set, especially producing the largest music library of any game available, and we wouldn't have been able to release as much outstanding content without the support of our amazing community," wrote Harmonix in February.